\documentclass{standalone}
\usepackage{tikz}
\usepackage{ctex,siunitx,ninecolors}
\setCJKmainfont{Noto Serif CJK SC}
\usepackage{tkz-euclide}
\usepackage{amsmath}
\usepackage{wasysym}
\usetikzlibrary{patterns, calc}
\usetikzlibrary {decorations.pathmorphing, decorations.pathreplacing, decorations.shapes,}
\begin{document}
\small
\begin{tikzpicture}[>=stealth,scale=1.0]
  \fill[top color=cyan!60,bottom color=cyan!40](-4,0)rectangle(4,-1.7);
  \draw[cyan!50!black](-4,0)--(4,0);
  \fill[brown](-1.0,0.1)rectangle(1.0,-0.1);
  \draw(0,-0.1)--(0,-1.65)--(0.05,-1.65)arc(0:-180:0.05)--(0,-1.65);
  \draw[<->|,thin](0.5,-0.1)--(0.5,-1.7)node[midway,right]{$h$};
  \draw[|<->|,thin](0,0.2)--(1.0,0.2)node[midway,above]{$r$};
\end{tikzpicture}
\end{document}